By the end of the mostly heady, sometimes punishing, experience of watching “Django Unchained,” you'll have a strong inkling why both Kurt Russell and Kevin Costner dropped out after agreeing to appear in Quentin Tarantino’s slavery-set revenge flick. Apparently, the potential benefit of allowing the director to work his renowned career-resuscitating magic wasn't enough to stomach having to repeatedly refer to actors playing slaves as “n**gers” in the middle of a plantation revival setting.

Tarantino has always reveled in being a cinematic iconoclast, but his latest B-movie pastiche promises to polarize casual fans and fanboys alike. Tarantino applies his raw, increasingly garrulous voice to a mashup that notably includes the Western black bounty hunter tableau of the 1975 blaxploitation film “Boss N**ger,” the bloody violence of Sam Peckinpah and the original “Django,” a 1966 Italian Spaghetti Western starring Franco Nero (who has a bit part in this iteration), and the grotesque depiction of slavery in the American South captured in the 1971 Italian pseudo-documentary “Goodbye Uncle Tom,” including a version of the film’s butcherous finale.

Set in 1858, “two years before the Civil War,” Django (Jamie Foxx) is a shackled slave rescued from his chain gang by Dr. King Schultz (Christoph Waltz), a German, Doc Holliday-esque former dentist turned bounty hunter who needs Django to collect the bounty for a trio of ruthless brothers Django can identify. In exchange, Schultz agrees to free Django from “this slavery malarky” and help rescue his wife, Broomhilda (Kerry Washington). Django takes a liking to bounty hunting — another “flesh-for-cash business,” as Schultz compares it to slavery — and the new partners soon track Broomhilda to the clutches of Calvin Candie (Leonardo DiCaprio), the debonair but barbarous proprietor of Candyland, a plantation where Candie breeds male slaves for sport fighting.

While Foxx is able but surprisingly unmemorable, Waltz sinks his teeth into Tarantino’s verbose dialogue, like he did as a Nazi officer in “Inglourious Basterds.” DiCaprio goes with gusto where Russell and Costner dared not tread, but the supporting cast is highlighted by Samuel L. Jackson’s portrayal of Candyland’s house Negro, whose ceremonial unctuousness masks a malevolence toward anyone would might threaten his master’s house.

Admirers of Tarantino’s audacity, his dexterity with a camera (along with cinematographer Robert Richardson) and his encyclopedic knowledge of cinema will find satisfaction despite a 165-minute running time that could have stood being sheared down a half-hour or so. Structurally, this is one of Tarantino’s most straightforward films. Still, there are a number of glaring plot holes and historical inaccuracies — e.g., the use of dynamite and other weaponry years before they were invented. They're the sort that routinely crop up in Tarantino’s work and should no longer be waved away as artistic flourish, particularly considering his recent criticism that the 1977 miniseries “Roots” “oversimplified” slavery and didn't “ring true.”

Tarantino deserves credit for committing many of slavery's horrors to film, including bracing scenes of slaves being beaten, eaten by dogs, stripped, smeared with blood, face-branded and pitted in so-called “Mandingo fights.” However, the awful reality of the antebellum South was far, far worse, and Tarantino particularly pulls his historical punches in the depiction of women, limiting himself to allusions of coerced prostitution without the rape and rank sexual abuse that ran rampant in the plantation culture. Apparently, even Tarantino knows that unmasking facts must be balanced against public appetites and the MPAA ratings board.

The biggest trouble with “Django Unchained” isn't hearing the n-word more than 110 times, by some counts. Indeed, such overuse almost acts to neuter the term of its inflammatory function. Instead, while Tarantino claims he wants the film to start a conversation, the real problem is that it doesn't have very much to say. Setting entertainment amid trying times is nothing new to cinema, but cloaking it with the shroud of truth is Tarantino wanting to have his layer cake and eat it too. It also opens Tarantino up to criticism that he is exploiting slavery's scourge for pop consumption and self-aggrandizement.

A scene like the metaphorical undressing of the masks worn by a group of Klansmen is not only overlong, but it's indicative of the easy, banal chuckles Tarantino deploys throughout “Django Unchained” under the guise of social satire. It's small compensation for audiences asked to surrender their racial sensibilities at the theater door.